Profinet connexion loss with PN/PN coupler

[JEANST]

Dear experts
i have an installation running with S7-1515 and a quite huge profinet network.

i encounter an issue with a Siemens PNPN coupler (6ES7 158-3AD10-0XA0 v4.2)
it has been configured and it's working well, to exchange datas
with another simatic plc.
but every day afternoon i have some short periodic connexions loss. the PNPN coupler disappears then re-appears from the network.

1s-2s around every 2h. it goes again well during the night, in general in the morning i have no problems.



i give you some elements

the distance between the switch and the PNPN coupler is approx 90m (a little bit less than 100m) so it's quite long but not more.
I must precise we had a problem at the startup i don't understand. by direct connecting the profinet cable on the coupler, the link leds LK1/2 doesn't flashed, we must had to install a switch then connect the profinet cable on it then add a standard ethernet cable to have the link.


the diagnostic buffer says, check wiring/network..



Do you think lenght, quality of the cable, temperature, proximity of power cable and so on.. should cause some kind of problem.


other question, the update time of the profinet is today 2ms. If i set it longer e.g. 8/16ms could this improve the stability ?


if somebody have an idea



Thanks

 

[JesperMP]

Checked the equipotential connection between the control cabinets of the Profinet network ?
Also check that the screen of the cable is properly clamped on an earth bar, not merely terminated in the connector.

I dont have that much experience with long Profinet cables. You can specify the lengths in the topology, and that will automatically add time for propagation delays. That is in the microseconds range, not milliseconds, so not sure how much change it will do. But worth checking.

 

[AlfredoQuintero]

Is your LAN cable built on site, or did you purchase the LAN cable for the distance you are using? if it is a built-on site, are you using industrial grade Ethernet attachable connector? or are you using office-grade type of LAN connector? Do you have a picture of the cable on one of its ends? if you have confirmed communication, then software issue is almost ruled-out. You need to think of a hardware problem, such as electric-level issue as suggested by Jesper above, or otherwise defective media, media in the border line condition that works sometimes and others does not.